if you are using Joomla then check out the JED there is at least on Joomla / OSticket bridge component had a play a while back with one called osticky ? I think there is probably at least one more by now..?

is it possible to do this if we cannot store any php files on the external website's server? our website is hosted on a cloud system that only allows the construction of basic html pages, we cannot store any actual files on the server.